Madeline Santarelli, the 35-year-old co-star of the new suburban-based reality TV show, “The Capones,” died Monday of liver and lung cancer, according to the Reelz cable network and a longtime family friend.

Santarelli didn’t even know she was sick until a few months ago, when after experiencing abdominal pain, she learned she had stage 4 cancer, said Dominic Capone, who also stars on the show and was her close friend for the past 20 years.

“It took over so fast,” Capone said Monday night.

Santarelli had moved back in with her parents in Chicago, so they could care for her, Capone said.

Santarelli is the focus of the series’ third episode, which coincidentally airs Tuesday and was the subject of an 80-person viewing party at Capone’s Restaurant & Pizzeria in Lombard, where the TV show is based.

Santarelli worked a variety of jobs at the restaurant, including hostessing and catering.

Capone says the party is going to continue, even though the show — about finding Santarelli her own apartment — will be “hard to watch.”

“She had such an outgoing personality … that’s what I loved about her,” Capone said. “She had a heart of gold.”

Funeral arrangements were not available Monday night.

The Reelz network, which airs “The Capones,” offered prayers and sympathies to the family.

“Madeline Santarelli was a beloved Capone family friend and will be greatly missed,” the network said.